My parents have a huge tree stump left from the felling of a sycamore which was becoming dangerous in their front garden. The stump is still growing and forcing the wall down between themselves and next door and has to be stopped. Digging it out is an impracticality due to its position. What is there out there to kill this stump reasonably efficiently without the use of major chemicals.
I have heard that i can drill holes in it and pour diesel into it, not something that i want to do. I have also heard that if you put copper nails etc into the stump they will react with the sap and kill it.
Any thoughts?

Can't you innoculate it with some interesting spawn? I am absolutely certain this is a possibility but can't for the life of me remember where I saw it (prob'ly bin readin' agin Bugs, oughter know my station in loife by now )

You can get stump rotting stuff in garden centres, probably not in the organic section. IIRC its crystals which you use to cover the top of the stump and then tape a plastic bag over the top. No idea what's in it mind.

How about growing mushrooms in it? According to the blurb I got with my pack of mushroom "dowels", if you seed the stump with mushroom spawn, it will eventually do for the stump AND you get a lovely crop of 'shrooms to boot.

mushrooms sound great, however will this destroy the stump in a couple of years which is realistically all i have before the wall will become completely unsafe and then the cost will start to get silly.(Its an eight foot double brick which is really starting to bend nicely)

Decided, mushrooms for a couple of seasons. If they don't rot it down quickly enough or prevent damage becoming too much then i will chop it out, lets hope the mushrooms do their job and provide some food at the same time